Lock.



PATENTED JAN. 30 E. H. F. KROHN.

LOCK.

APPLICATION FILED OUT. 28. 1902.

UNITE STATES PATENT OFFICE.

Specification of Letters Patent.

Patented Jan. 30, 1906.

Application filed October 28, 1902. Serial No. 129,159.

To all 1071,0711, it may concern:

Be it known that I, EMIL HERMANN FRITZ KROHN, technologist, a subject ofthe German Emperor, residing at the free town of Hamburg, Osterstrasse159, in the State of Ham burg and Empire of Germany, have inventedcertain new and useful Improvements in or Connected with Locks, of whichthe following is a full, clear, and exact description.

The present improvement in door and similar locks consists in thecombination therewith of a supplementary lock operated by means of aspecially-constructed key and serving to disconnect the latch with itshandle in the act of shooting the lock-bolt, so

that thereafter if the lock-bolt be withdrawn by means of another key orby picking the latch will remain locked and cannot be retracted by meansof its handle or until the connection between thelatch and its handlehas been restored by means of the proper key or a special key.

In the accompanying drawings, Figure 1 is a front view of the main lock,the supplementary lock being shown in dotted lines. Fig. 2 is a frontview of the supplementary lock. Fig. 3 is a longitudinal section throughboth locks on the line A B, Fig. 1. Fig. 4 shows a key adapted tooperate both locks simultaneously; and Fig. 5 a key for operating thesupplementary lock alone, as hereinafter described.

Referring first to the key shown in Fig. 4, it will be seen that inaddition to the bit a for the main lock-bolt h there is an extra bit I),disposed on each side of same. In operation only one of these bits I) isused at a time for looking or unlocking, the one which comes into actiondepending upon which side the lock is actuated from.

The T-shaped bar 0, which is acted on by the ordinary spindle sleeve incustomary manner, is under my improvement connected with the latch d,not directly, but through the intervention of a section f, pivoted tothe latch d and interlocking with the bar 0, as clearly shown in Fig. 1,in order that the latch may be disconnected from the spindle-sleeve ofthe handle. Above the barsection j, which is hinged to the latch d, aspring 6 is provided, which presses the bar-section f downward on thetop of a supplementary lock-bolt g, which is movably secured to thelock-casing by means of a guiding-band g and which is adapted to bemoved down or up vertically by means of one of the extra bits I) of thekey, Fig. 4, in shooting or retracting the lock-bolt h or independentlyby the special key, Fig. 5. If now the door is to be locked and the keyis turned, the supplementary bolt 9 will be moved downward in the act ofshooting the lock-bolt h, and consequently will release the barf, whichis pressed downward by the spring 0 bearing on it, and therebydisconnected from the bar 0. Then if an attempt be made by anunauthorized person to open the lock, though the main bolt it may beretracted, yet the catch d remains bolted and cannot be withdrawn byturning the handle and spindle-sleeve nor can the person attempting toopen the door observe that the latch is bolted, because the handle isalways returned to its old position by the spring 01, as in ordinarylooks.

The key represented in Fig. 5 is used solely for connecting anddisconnecting the supplementary lock.

Having thus described my invention, the following is what I claim as newtherein and desire to secure by Letters Patent:

1. In a lock of door-lock type, the combination with the ordinarylock-bolt h, springlatch d and bar 0 for retracting said latch; of adetachable connection f between said bar 0 and spring-latch d; and asupplementary lockbolt 9 adapted to be operated by a special key andcontrolling the connection of the spring-latch with the means forretracting the same, substantially as described.

2. A door-lock comprising a main locking mechanism, a spring-latch,disconnectible means for operating said latch operating mechanism, and asupplementary locking mechanism, disposed between, and operating inconjunction with said lock and latch operating mechanisms, substantiallyas and for the purpose specified.

In witness whereof I subscribe my signa ture in presence of twowitnesses.

EMIL HERMANN FRITZ KROHN.

